Wales captain Ryan Jones has been called into the British & Irish Lions squad after flanker Stephen Ferris was ruled out of the remainder of the tour with a knee injury.

Grand Slam winner Ferris, a strong candidate to clinch a Lions Test place against world champions South Africa on Saturday week, suffered the injury in training on Monday and scans today revealed a Grade 2 tear to his medial collateral ligament that will require 4-6 weeks recovery.

Jones, who joined the 2005 Lions tour in New Zealand as a replacement and ended up playing in the Test series, will link up with the squad in Cape Town on Thursday.

"He had the scan on Tuesday morning that showed he had a grade two tear to his medial collateral ligament," head coach Ian McGeechan confirmed in a statement. "This usually requires a four to six-week recovery period and is severe enough to mean he will miss the rest of the tour. Therefore, with six matches left on tour after Wednesday's match against the Sharks, we believe we need to fly out a replacement as cover for the back-row.

"Ryan is on the standby reserve list and of course has been playing for Wales over the last few weeks in the USA and Canada," said head coach Ian McGeechan. "He will fit right in as he knows a lot of the players and of course he was a Lions replacement on the 2005 tour to New Zealand. In fact on that tour he showed how competitive he is as an individual by forcing his way into the Test side for all thee matches against the All Blacks."

Jones' arrival will take the compliment of Welsh international players on the tour to fourteen, with eight more WRU personnel in the coaching and back room staff including Tour Manager Gerald Davies. He will fly out to South Africa with Neil Jenkins who this week was called into the squad as kicking coach for the rest of the tour.

"I am delighted to have received this call-up and I am just really looking forward to joining the squad later this week," said Jones. "Obviously it is disappointing for Stephen Ferris who is a superb player and I wish him a quick and full recovery from his injury. I am anxious to help the Lions in any way I can and I recognise how this is a great honour for me and my family."

There was also worrying news about another squad member - Wales international Leigh Halfpenny. The Cardiff Blues wing arrived late in South Africa after remaining at home for intensive treatment on a thigh injury. He made his first tour start against the Cheetahs last Saturday.

"He has aggravated his old injury," said Lions assistant coach Shaun Edwards. "He recovered very quickly from the last time. It is nowhere near as bad as that, so we will wait and see. Scans are amazing things nowadays, so we will wait to see what that says.

"He was doing some extra training at the end of a session, practising his kicking, and he just felt it strain up a little bit."